Aerial vehicles, such as unmanned aerial vehicles (UAVs), have been developed for a wide range of applications including surveillance, search and rescue operations, exploration, and other fields. Such UAVs can often be controlled and navigated by a remote controller. In some instances, UAVs can be vehicles capable of sensing and navigating through an environment without guidance from a human controller.
One commonly used autonomous navigating technique is visual navigation by virtue of cameras. The UAVs may autonomously determine its state information, including a height, a speed, a direction, a coordinate and a distance to certain object, during visually navigated flight. However, a deviation may occur between the autonomously determined state information and the actual state. The deviation becomes larger over time, thus a reliability of the visual navigation may be reduced.